2009-04-06_REVISION - C1982056 (20)

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pit, the rock cuttings are separated or settled out and the water is allowed to drain back or is pumped back into the hole for re-use. The cuttings volume will be approximately 12,500 cy. Once the cutter head reaches the coal seam, the cutter head will be disassembled and removed from the A-leg derrick. Using the same A-leg derrick, the excavated shaft will then be lined to a nominal 6-foot inside diameter using a hydrostatic steel liner. The steel liner sections will be pre-fabricated off-site, hauled to the site and field welded in 30-50 foot joints. The liner will be floated into place. This is accomplished by securing a steel bulkhead to the bottom joint and leaving the excavated hole full of water while the liner is being lowered into place. By calculating the buoyancy of the liner, and adding water to the capped liner column, as needed, the liner is easily and safely lowered into position. Once the liner is in place, a - nominal-9-inch-thick grout seal will-be- pumped between the strata-and liner.- The grouted-steel-- liner will serve to isolate the Twentymile Sandstone from the Wadge Overburden. As previously noted, TCCplans to pressure grout the Twentymile Sandstone to minimize seepage to the shaft. This will help assure that, after final closure, groundwater from this unit will be confined and not seep down the inside of the shaft. Upon completion of shaft drilling and steel liner installation for both shafts, the cuttings pit will be dewatered. Excess water will be hauled to the Area 1 Pit, and the remainder will be allowed to evaporate. After dewatering the cuttings pit and allowing the cuttings to consolidate and dry-out, the collection pit and cutting materials will be covered with stockpiled materials from the shaft collar excavation, graded and revegetated with a temporary cover. A sign(s) will be posted designating the temporary mine development waste pit. The cuttings and shaft collar excavation materials will be utilized to re-fill the shafts during eventual reclamation of the shaft installation. As shown on Map 23, additional entries will be driven from the 18-Left gate-road to the north to connect with the two ventilation shafts. The entries will be driven in the same manner as is used in TCC's development work, i.e. continuous miners and shuttle cars. Following completion of shaft boring and casing operations and removal of the drilling equipment from the site, emergency hoist equipment, consisting of an escape capsule, hoist _derrick, hoist drive unit, control equipment and 18 x 24 foot pre-fabricated metal hoist house, and a pre-fabricated propane-fired shaft heater and ducting will be erected/installed on the previously constructed intake shaft concrete pad. The shaft heater will be connected to a propane supply tank, mounted on prefabricated concrete saddles, and a buried electrical cable. Similarly, a fan enclosure (fan shroud), silencer, and electrical control building will be erected on the previously constructed exhaust shaft concrete pad, and the fan, fan drive motor, and electrical control, monitoring, and communication systems will be installed. It is presently anticipated that the 400 hp, 90,000 cubic-foot per minute Robinson Fan and associated equipment will be relocated to the 18-Left Ventilation Shaft from the EMD Ventilation Shaft location. A chain-link security fence with a locked gate will be constructed to enclose the intake shaft and emergency hoist installation. Following commissioning, the shaft pad site and access road will be cleaned-up and surface areas graded and dressed. In order to comply with new Mine Atmosphere Control (MAC) regulations, under the jurisdiction of the Mine Safety and Health Administration (MSHA), and minimize surface disturbance, TCC will utilize the previously drilled and cased exploration borehole as a MAC borehole for nitrogen injection into abandoned mine gob areas. The 8-inch pipe installed